1. Field of the Invention
The present invention relates to manufacturing of a semiconductor device, in particular, to a defect detection system, a defect detection method, and a defect detection program for detecting the cause of a defect of the semiconductor device.
2. Description of the Related Art
One of the problems to be addressed in enhancing the productivity of the semiconductor device such as a large-scale integration (LSI) circuit is to enhance the yield. It is important to analyze the yield loss, and ascertain and improve the process, manufacturing device, or design conditions that lead to the cause of yield loss at an early stage in order to enhance the yield. However, for example, the LSI is produced through hundreds of steps and manufacturing devices. Thus, it is generally very difficult to detect that the cause of a defect that occurred in the LSI once.
The result of the wafer test, which is the electrical characteristic test, performed after the termination of the wafer process of the semiconductor device manufacturing provides an important clue in ascertaining the cause of the defect. This is because the wafer test is performed on the wafer in a wafer shaped state. That is, the position of the defective portion in the wafer surface is detected in the wafer test by mapping displaying the wafer test result in the wafer surface. A typical mapping display is a failure bit map (FBM) acquired in memory products. In logic products, memory mixed logic products, or the like, a pass/fail map in which the non-defective product (pass) or defective product (fail) is mapping displayed in units of chip partitions.
The distribution of the defect in the wafer surface is broadly divided into two types of a “random defect” that occurs equally in the wafer surface and a “clustering defect” that occurs deflected to one part. Most of the time, the occurrence of the clustering defect arises from systematic causes resulting from process, manufacturing device and the like, which is a great cause in lowering of yield. The defect resulting from process, manufacturing device and the like produces a defect pattern inherent in the process or the manufacturing device on the wafer surface. Therefore, pattern analysis of the clustering defect is considered as the clue to ascertain the cause of occurrence of defects.
The defect detection in the semiconductor device manufacturing is performed by researching the manufacturing history in a clean room for a plurality of wafers or a plurality of lots in which the same clustering defect has occurred. For example, a method of researching whether or not the same step is processed by the same manufacturing device for the plurality of wafers in which the same clustering defect has occurred, and performing a significant difference test between the manufacturing devices for the feature quantity obtained by quantifying the clustering defect (see, e.g., Jpn. Pat. Appln. KOKAI Publication No. 2002-359266).
However, the clustering defect in manufacturing of the semiconductor device does not only appear as a pattern in the wafer surface. For example, the clustering defect resulting from the lithography step appears as a pattern in the processing unit of the lithography step, that is, the shot area. The state of the processing process differs between the central part and the peripheral part of the memory cell array in memory products, and thus defects occur in the state deflected towards the peripheral part of the memory cell array, in which case, the pattern of the clustering defect is produced in the chip partition.
Conventionally, pattern classification of the clustering defect and defect detection are performed using the wafer test result indicating the defects in units of partition with a size larger than or equal to a size of the chip partition. However, when the wafer test result indicating the defects in units of partition with a size larger than or equal to the size of the chip partition is used, pattern classification of the clustering defect and defect detection in the shot partition or the chip partition cannot be performed, and the cause of defect of the semiconductor device cannot be detected at high precision.